Sanjay Basu, Assistant Professor of Medicine at the Stanford University Prevention Research Center, answers questions from PLOS Social Media Associate Sara Kassabian.
[Post updated on April 7, 2016]
The burden of non-communicable diseases (NCDs) is growing globally, with an estimated 38 million people dying from chronic conditions, the majority of whom live in low- and-middle income settings. Diabetes contributes substantially to this burden, with about 410 million people living with diabetes in 2013. Experts project this burden will rise to an estimated 642 million people living with the condition by 2040, if trends continue.
Curbing the incidence of NCDs such as diabetes is critical to achieving the goal of one-third reduction in premature mortality from chronic diseases by 2030 (SDG 3.4). Developing stronger diabetes prevention strategies is necessary to mitigate the burden of this condition.
In recognition of the growing global burden of diabetes, PLOS Medicine has announced a call for papers for a special issue on diabetes prevention, whose editors include esteemed scientists Professor Nick Wareham and Professor William Herman.
To put the spotlight on different population-level strategies for curbing diabetes, we invited Dr. Sanjay Basu, a specialty consulting editor for PLOS Medicine and physician and epidemiologist with expertise in type 2 diabetes, to participate in our February 24, 2016 ‘PLOS Science Wednesday’ redditscience ‘Ask Me Anything’ series. Dr. Basu discussed (see completed AMA link below) his research published in PLOS Medicine assessing unique methods for diabetes prevention; including a 2014 paper investigating the effectiveness of a sustained tax on sugar-sweetened beverages (SSBs) and a 2015 paper evaluating the effectiveness of large-scale community screenings in India.
Taxation on sugar and/or SSBs has been implemented effectively in Mexico, another country facing an elevated burden of obesity and diabetes. In “Averting Obesity and Type 2 Diabetes in India through Sugar-Sweetened Beverage Taxation: An Economic-Epidemiologic Modeling Study ” Dr. Basu and colleagues calculated how a hypothetical tax on SSBs would impact prevalence of overweight and obesity, and type 2 diabetes in India. The researchers projected that a hypothetical 20% excise tax on SSBs would reduce the prevalence of overweight and obesity by 3% and type 2 diabetes by 1.6% between 2014-2023. In fact, their findings showed a SSB tax would be more effective than their initial projections, reducing overweight/obesity prevalence by 4.2% and incidence of type 2 diabetes by 2.5% in India. Dr. Basu’s findings indicate that taxation can be a high-impact behavior change intervention to mitigate the increasing prevalence of diabetes.
In “The Health System and Population Health Implications of Large-Scale Diabetes Screening in India” Dr. Basu and colleagues used a validated microsimulation model to assess the effectiveness of three survey-based screening instruments and one random glucometer-based screenings to identify individuals at high risk of developing type 2 diabetes. They found that between 126 million and 273 million diagnoses using these tools would be “false positives” at a total estimated cost of US$169 million and US$567 million. These findings showed that using currently available screening instruments will be a substantial financial cost to taxpayers and will yield many incorrect results.
Selected Q&A with Dr. Sanjay Basu
In advance of his February 24, 2016 AMA, Dr. Basu sat down with PLOS Social Media Associate and Student Blog Editor Sara Kassabian to discuss the future of diabetes prevention. A selected Q&A with Dr. Basu is included below. Please note, some responses have been edited for brevity.
The new global health agenda has identified a one-third reduction of premature mortality from NCDs by 2030 (SDG 3.4) as a primary target. Clearly, the growing burden of diabetes is included in this mandate. Do you feel this issue has received adequate attention from global health policymakers and other stakeholders? Why or why not? What do you think are some of the factors contributing to its visibility or lack of visibility in global health?
The substantial burden of NCDs has certainly been received by a lot of speeches and reports from high-level commissions and institutional bodies. My concern is that this level of visibility may poorly translate to actual improvements in populations’ access to evidence-based prevention and treatment, particularly in low- and middle-income countries. I fear, based both on anecdotal experience and our attempts to gather data on this issue internationally, that much of the current landscape of NCD response is through minimally-effective or ineffective provision of individually-directed lifestyle advice or wellness programs, or medical care characterized by inadequate access to quality therapy and long-term chronic care management. The disconnect between high-level visibility of the issues and day-to-day implementation of effective prevention and treatment seems to be a major barrier to gaining meaningful progress in addressing NCDs globally, in my opinion.
In “Averting Obesity and Type 2 Diabetes in India through Sugar-Sweetened Beverage Taxation” you found that taxing sugar-sweetened beverages (SSBs), a policy that has been successful in Mexico, can mitigate rising obesity and type 2 diabetes in India. Why do you think that an indirect tax on sugar has encountered resistance in places like India and the United States? What are some of the barriers to taxation on SSBs?
The main challenge is political. There is both a tremendous amount of money being made on these products, and a tremendous amount of influence of industry on the political bodies that are charged with considering fiscal and regulatory interventions on these products, as described in books by Nicholas Freudenberg and Marion Nestle for instance. As one example of the political challenges faced by policymakers introducing fiscal regulations, after the Chief Economic Advisor for India proposed a tax on sugar-sweetened beverages on December 7, 2015, the CEO of PepsiCo had a meeting with the Prime Minister of India on December 10, 2015 and Coca-Cola threatened to shut all of its plants in India on December 11, 2015. The response therefore was swift, severe, and directed at a high level of the political chain of command.
What policy measures have been shown to work in terms of reducing incidence of type 2 diabetes? What doesn’t work and why?
I don’t know of any. Demonstrating a reduction in type 2 diabetes incidence through a policy measure is extremely difficult scientifically: one would have to follow groups of people for decades before the impact of policy measures (which are, for example, focused on modifying the broad food environment) would potentially manifest as a reduction in diabetes incidence. We would also need to somehow control for numerous factors that differ between people exposed to a policy and those not exposed to a policy (who are rarely very similar; economists like to term this problem “endogeneity”). Since the policy-level strategies to prevent diabetes incidence are just being instituted now, such as through Mexico’s SSB tax, I don’t see any compelling evidence to date for reductions in diabetes incidence, which will take years to observe if they can be observed at all in the setting of diffuse effects among large populations with no clear control group and the potential from tremendous statistical confounding in long-term population wide assessments. In public health, however, we rely on the precautionary principle: what might be the safest strategy, under current evidence and knowledge, to protect the public? It’s under this premise that measures like the SSB tax are found to be compelling despite the inherent challenges of evaluating their efficacy in the real world.
In “The Health System and Population Health Implications of Large-Scale Diabetes Screening in India” you found that large-scale community-based screenings will result in hundreds of millions of false positives, indicating that widespread screening for diabetes in India would not be cost effective. Following publication of this prediction, have India’s health policy makers shifted their stance accordingly?
Yes, the issue was that none of the risk scores was very good, so many people are being given a diagnosis they don’t have, and vice versa. The policy makers in India have shifted towards using appropriate testing strategies focused on improving primary prevention (e.g., through improvements in the food environment) and secondary prevention (e.g., treating hypertension and hyperlipidemia among people with type 2 diabetes, which significantly reduces the risk of the major causes of death). However, I do still see some “social entrepreneurs” who are mistakenly putting type 2 diabetes “risk calculators” into smartphone apps and advertising them online, despite the really poor predictive power (and risk of lots of false positive and negatives) that these have.
What are some of the current unknowns around diabetes prevention? What are some of the innovations the medical community still needs to address in the future?
See above. We have to improve risk prediction, and look to societal solutions and fiscal and regulatory solutions, rather than just individually-directed solutions or those focused on health education and health promotion, given how poor the evidence is for the latter.
What do you feel are the present and future costs of preventing diabetes?
I think most cost studies are really hard to believe; they are based on projections of the burden of illness that themselves are really impossible to validate. How much it will cost depends on how we decide to address it.
Read the completed 2/24/16 PLOS Science Wednesday redditscience AMA transcript of Sanjay Basu (Stanford University), discussing The Health System and Population Health Implications of Large-Scale Diabetes Screening in India and Averting Obesity and Type 2 Diabetes in India through Sugar-Sweetened Beverage Taxation. 2/24 AMA archive. Read the PLOS Medicine articles here and here.
Featured image credit: Alden Chadwick, Flickr